This invention relates generally to a container for transporting bulk goods and, more particularly, to a transportable container comprising a flexible bag for receiving particulate fill material and a spirally wound overwrap for stabilizing the bag.
Typical containers utilized for transport of bulk particulate fill material are inefficient, do not have a very large volume, and often require a large amount of manual labor be used in filling and handling of the container. Also these containers are typically stacked on top of each other during handling and transport, because the containers are not stabilized, this results in damage to the material.
Johnstone et al. discloses in U.S. Pat. No. 5,566,530 method for packaging of irregularly shaped articles, flowable granules, or liquids comprising placing an open framework on a pallet to create a space. The space is filled with the material and then a stretch wrap film is wrapped around the material and the framework. Finally the framework is removed from the film.
Williamson discloses in U.S. Pat. No. 4,113,146 a container comprising a spirally wound film to form an inner container, this is surrounded by a middle layer of spirally wound polyester filament, which is in turn surrounded by an single outer wrap sheet. The ends of the inner container are closed with ties and a support sling is located between the middle and outer layers. In U.S. Pat. No. 4,253,507 Williamson discloses a two ply inner tube covered by an over wrap that is bonded to the inner tube. One end of the inner tube is folded and sealed to form a closed bag like structure.
In U.S. Pat. No. 3,374,599 Sanders discloses a method comprising dropping the materials into a container mounted to a conveyor, placing a continuous tubular thermoplastic netting around the container, sealing one end of the netting, then dropping the netting and material out of the container onto a second conveyor where the other end of the netting is sealed. The netting may subsequently be heated to form a firmer package.
In U.S. Pat. No. 5,353,936 Dockstader et al. discloses a protective tray for use in forming a palletized load of stacked bags of particulate material. The protective tray comprises double wall corrugated cardboard or rigid plastic and in a preferred embodiment it is surrounded by a stretch wrap that encircles the protective tray and the bags.
Connolly discloses in U.S. Pat. No. 4,136,501 a system comprising wrapping a palletized load with a sheet of thermoplastic netting material. Finally, Humphrey discloses in U.S. Pat. No. 4,299,076 a system for wrapping a stabilizing overwrap around a load mounted on a pallet, which is placed on a rotating turntable. The overwrap has a width that is equal to the height of the load and with each rotation the overwrap undergoes successive increasing stages of tension and stretch.
The present invention provides a transportable container that is a space and cost savings alternative to other know containers. The transportable container of the present invention generates hoop forces on the particulate fill material that immobilize the material in the container, make the container rigid, and prevent the material from shifting during transport thereby preventing damage to the material. The hoop forces promote contact between the particles of the particulate material, thereby both stabilizing and compressing the material, such that the container of the present invention can hold up to three times the amount of particulate material as compared to a conventional tote. Further advantages include reduced contamination of the particulate material, reduced stacking damage, reduced spoiling, and reduced trapping of the material in the container. Finally, the present container allows easy identification of the contents because it is preferably formed from clear materials.
In one embodiment the present invention is a transportable container for bulk goods comprising: a bag having a closed base and an open top, the open top in a folded over position; a bottom support adjacent the closed base; a particulate material in the bag; and an outer wrap spirally wrapped around the bottom support and the bag, the outer wrap securing the bag to the bottom support and the open top in the folded over position.
In another embodiment the present invention is a method of forming a transportable container for bulk goods comprising the steps of securing an open top of a bag in an open position and supporting a base of the bag; filling the bag to a predetermined level with a particulate material; detecting a fill level of the particulate material in the bag; spirally wrapping an outer wrap around the bag in an upward direction up to the predetermined level; releasing the open top of the bag and moving it to a folded over position then spirally wrapping the outer wrap around the bag in a downward direction to secure the open top in the folded over position.
These and other features and advantages of this invention will become more apparent to those skilled in the art from the detailed description of a preferred embodiment. The drawings that accompany the detailed description are described below.